Baxter A B, Lazarus S C, Brasch R C
Department of Radiology, University of California, San Francisco 94143-0628.
Invest Radiol. 1993 Apr;28(4):308-12. doi: 10.1097/00004424-199304000-00009.
To investigate the mechanism of anaphylactoid reactions to contrast media, in vitro histamine release induced by magnetic resonance imaging, and iodinated contrast agents was examined in a dog mastocytoma cell line.
Two gadolinium (Gd)-based magnetic resonance contrast agents, Gd diethylenetriamine pentaacetic acid (Gd-DTPA), dimeglumine, and Gd-bismorpholide, and two iodinated contrast agents, diatrizoate meglumine and iohexol, were incubated with histamine-containing canine mastocytoma cells. Release of histamine into the supernatant was determined at various contrast-medium concentrations after incubation at 37 degrees C for 30 minutes.
Iodinated and Gd-based contrast agents caused release of histamine from mastocytoma cells at similar concentrations (50-150 mM). Mannitol, an osmotic stimulus, caused release of histamine only at concentrations greater than 1,000 mM.
Histamine release from canine mastocytoma cells does not appear to be solely due to osmotic effects, but results from direct stimulation by contrast media. For all agents examined, the concentration at which in vitro histamine release occurs far exceeds the serum contrast media concentration expected in routine clinical application. Direct release of histamine from mast cells does not completely explain the pathogenesis of idiosyncratic anaphylactoid responses to contrast media.
为研究类过敏反应对造影剂的机制，在犬肥大细胞瘤细胞系中检测了磁共振成像和碘化造影剂诱导的体外组胺释放。
将两种钆（Gd）基磁共振造影剂钆二乙三胺五乙酸（Gd-DTPA）、葡甲胺和钆双吗啉，以及两种碘化造影剂泛影葡胺和碘海醇与含组胺的犬肥大细胞瘤细胞一起孵育。在37℃孵育30分钟后，测定不同造影剂浓度下上清液中组胺的释放量。
碘化造影剂和钆基造影剂在相似浓度（50 - 150 mM）下均可引起肥大细胞瘤细胞释放组胺。甘露醇作为一种渗透刺激物，仅在浓度大于1000 mM时才会引起组胺释放。
犬肥大细胞瘤细胞释放组胺似乎并非仅由渗透作用引起，而是由造影剂直接刺激导致。对于所有检测的试剂，体外组胺释放发生时的浓度远远超过常规临床应用中预期的血清造影剂浓度。肥大细胞直接释放组胺并不能完全解释对造影剂特异质性类过敏反应的发病机制。
